The present disclosure relates to respiratory therapy systems and devices. More particularly, it relates to patient interface assemblies configured to couple to respiratory therapy systems for delivery of medication.
A wide variety of respiratory therapy devices are currently available for assisting, treating, or improving a patient's respiratory health. For example, positive airway pressure (PAP) has long been recognized to be an effective tool in promoting bronchial hygiene by facilitating improved oxygenation, increased lung volumes, and reduced venous return in patients with congestive heart failure. More recently, PAP has been recognized as useful in promoting mobilization and clearance of secretions (e.g., mucous) from a patient's lungs. In this regard, expiratory positive airway pressure (EPAP) in the form of high frequency oscillation (HFO) of the patient's air column is a recognized technique that facilitates secretion removal. In general terms, HFO reduces the viscosity of sputum in vitro, which in turn has a positive effect on clearance induced by an in vitro simulated cough. HFO can be delivered or created via a force applied to the patient's chest wall (i.e., chest physical therapy (CPT)), or by applying forces directly to the patient's airway (i.e., breathing treatment, such as high frequency airway oscillation). Many patients and caregivers prefer the breathing treatment approach as it is less obtrusive and more easily administered. To this end, PAP bronchial hygiene techniques have emerged as an effective alternative to CPT for expanding the lungs and mobilizing secretions.
Various HFO treatment systems are available for providing the respiratory therapy (high frequency intrapulmonary percussive therapy) described above (as well as other therapies and/or ventilation). In general terms, the high frequency intrapulmonary percussive (HFIP) system includes a hand-held device establishing a patient breathing circuit to which a source of positive pressure gas (e.g., air, oxygen, etc.) is fluidly connected. In this regard, the system further includes a driver unit that acts upon the supplied positive pressure gas, creating an oscillatory pressure profile or otherwise effectuate intermittent flow of gas into the patient breathing circuit, and thus percussive ventilation of the patient's lungs. With this approach, the patient breaths through the breathing circuit's mouthpiece (or mask), that in turn delivers the generated high-flow, “mini-bursts” of gas to the patient's airways. The pulsatile percussive airflow periodically increases the patient's airway pressure.
Current HFO treatment systems can also be used with a nebulizer to deliver aerosolized medication to patients. The nebulizer can be fluidly coupled to the driver unit to deliver medicated gas to patients through the patient interface circuit. Conventional configurations of patient interface circuits entrain medication within a device with ambient air to deliver the medicated gas to the patient. These configurations can contribute to medication “knock down”, wherein build-up of medication within the device increases and the amount of medication delivered to the patient is reduced. Thus, a need exists for improved respiratory therapy systems, in particular patient interface assemblies that deliver medication to a patient.